Shipboard antennas often use HF frequencies that require the entire ship to act as an antenna. For particular HF frequencies, heretofore, it has not been possible to achieve any reasonable transmit efficiencies. This requires enormous transmit power and results in other problems such as interference with collocated receivers. Interference mechanisms take various forms such as cross-modulation, broadband noise radiation, desensitization, intermodulation, and spurious emissions. Devices that address many of these are the comb linear amplifier combiner (CLAC) and the comb limiter combiner (CLIC). CLAC's technique of putting the high-power amplifiers (HPAs) close to the antenna enables the use of lossy narrowband high Q filters that cleans up adjacent channel interference. CLIC's technique of putting at the front end of the receiver a bank of parallel bandpass filters having contiguously adjacent passbands that together span the entire bandwidth of the receiver enables reduction in adjacent channel interference. Thus collocated radios can tune closer in frequency, making more efficient use of the spectrum. Yet even more efficiency is achievable with the present aspects disclosed herein, which enhance the capabilities of CLIC and CLAC by attacking issues not previously or adequately addressed. In ship environments with multiple transmit and receive frequency ranges and/or antennas, these systems have not met satisfactory performance for high speed communications.
High Temperature Superconducting (HTS) material is comprised of an alloy of various exotic materials. They can reach zero resistance, and thus improve efficiency when used in a CLIC or CLAC. However, certain limitations of HTS alloys used in CLIC or CLAC systems have not previously been understood or addressed.